VENNEGUES , Philippe

Les nitrures d'éléments III et les alliages à base de ZnO, semi-conducteurs à large bande interdite étudiés au CRHEA, cristallisent dans la structure hexagonale wurtzite. Cette structure a la particularité d'être une structure polaire et les polarisations internes ont donc une forte influence sur les propriétés des hétérostructures à base de...

The absolute epitaxial relationships between III-nitride films and R-plane sapphire are investigated using convergent beam electron diffraction. The resulting relationships are found to be[1−100]III-N‖‖[11−20]sapphire and [0001]III-N‖‖[−1101]sapphire, respectively. The O–Al bonds in the sapphire surface are antiparallel to the N-III bonds in...

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In a polycrystalline γ-γ′ nickel-based superalloy, γ′ precipitates with a close-to-twin orientation relationship to their surrounding matrix (named T-type precipitates) are found in recrystallized grains located near specific unrecrystallized grains (named recovered grains). This type of γ/γ′ interface has not been reported in literature...

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This paper demonstrates the existence of large γ' precipitates (several micrometres in diameter) that are coherent with their surrounding matrix grain in a commercial γ–γ' nickel-based superalloy. The use of combined energy dispersive X-ray spectrometry and electron backscattered diffraction (EBSD) analyses allowed for revealing that surprising...

International audience

In this contribution, we performed the growth of a 3C-SiC/Si/3C-SiC layer stack on a Si(001) substrate by means of chemical vapor deposition. We show that, by tuning the growth conditions, the 3C-SiC epilayer can be grown along either the [111] direction or the [110] direction. The key parameter for the growth of the desired 3C-SiC orientation...